Clinical inertia, defined as lack of treatment intensification in a patient not at evidence-based goals for glycated hemoglobin (Alc), systolic blood pressure (SBP), or LDL-cholesterol (LDL), is a factor in about 80% of the 40 million office visits made each year by adults with diabetes in the U.S. Clinical inertia is a major obstacle to high quality diabetes care, and contributes to many potentially preventable macro vascular and micro vascular complications, premature disability and mortality, and at least $4 billion a year of potentially preventable health care charges in the U.S. In this randomized trial we evaluate two conceptually distinct but potentially synergistic interventions designed to reduce clinical inertia in the outpatient care of adults with type 2 diabetes. Intervention A is a Cognitive Behavioral Intervention (CBI) tailored to an individual physician's patterns of clinical inertia in diabetes patients. Intervention B is an Office System Redesign (OSR) Intervention that includes 4 monthly office visits with embedded real-time clinical decision support and accountability reporting by physicians after each visit. Both the Cognitive Behavioral Intervention and the Office Systems Redesign Intervention are conceptually powerful yet simple interventions based on customization theory and on our previous work. Eighteen primary care clinics, 80 eligible primary care physicians from those clinics, and 30 eligible diabetes patients per physician (N=2,400 patients) will be group randomized to one of four study arms: (1) Cognitive Behavioral Intervention (CBI) only, (2) Office Systems Redesign (OSR) only, (3) CBI plus OSR, (4) No intervention. The main dependent variable, clinical inertia, is measured as the proportion of patients not at evidence based Alc, SBP, or LDL goals whose drug therapy was not intensified in a defined 4-month period of time. We hypothesize that the CBI intervention alone, and the OSR intervention alone, will be superior to no intervention, and that there will be a positive interaction when CBI and OSR interventions are combined. Hierarchical logistic models (MLwiN) that accommodate nested data will be used to formally test study hypotheses. Detailed economic analysis will identify short-term direct medical costs related to interventions. The interventions have the potential to substantially improve the quality of diabetes care delivered in office practice, and could be disseminated to any office practice with access to automated diagnostic, laboratory, and pharmacy data. Results of this project will have significant clinical and policy implications.